Astonishing celebrity artefacts: from Jim Henson's first Muppet to the gun that killed John Lennon

It was while on a magazine assignment to photograph guns impounded in the New York Police Department’s Forensic Investigations Division that Henry Leutwyler chanced upon the murder weapon that triggered a deeply personal 12-year project.

A police officer was showing him around when he spotted a revolver lying on a stool next to a newspaper clipping about John Lennon.

The gun used by David Mark Chapman to kill John Lennon, photographed by Henry Leutwyler